There are several power meters that will work on Campagnolo cranksets:
Campagnolo Left Crank Arm Power Meters
Stages Cycling makes left-side crank arm power meters for Campagnolo cranks. These power meters replace your current Campy left-side crank arm and measure power generated by the left leg. They double the value to approximate total power.
Stages Carbon Campagnolo Record Power Meter 12S
This power meter is for Record 12-speed cranks.

Stages Carbon Campagnolo Record Power Meter 12S
Stages Carbon Campagnolo Super Record Power Meter 11S
This power meter is for Super Record 11-speed cranks.

Stages Carbon Campagnolo Super Record Power Meter 11S
Stages Carbon Campagnolo Super Record Power Meter 12S
This power meter is for Super Record 12-speed cranks.

Stages Carbon Campagnolo Super Record Power Meter 12S
Please note, these power meters attach a sensor to the inside of the left crank arm. On some bikes, there is not enough room between the left crank arm and the chainstay for the sensor to clear the frame. Therefore, you should make sure you have at least 10 mm of clearance for Stages power meters. Also, please make sure that you don’t have a bottom bracket mounted rear brake (used on some aero and TT bikes). Please refer to the image below.
Pros: More affordable than a crankset, easy to install, don’t have to change crankset
Cons: Measures left leg power only
Campagnolo Crankset Power Meters
Please note, with these options, you are replacing your entire Campy crankset.
power2max NGeco Campagnolo Power Meter Crankset
power2max NG Campagnolo Power Meter Crankset (The NG is an upgraded version of the power2max power meter with additional features and functionality.)
The power2max crankset comes with Campy crank arms and power meter spider. You can purchase the power meter with Campagnolo 12-speed chainrings, or use your own 11- or 12-speed chainrings if you already have them. power2max makes great power meters – we use them on many of our own bikes.

power2max NGeco Campagnolo Power Meter Crankset
SRM Campagnolo 12-Speed Power Meter
The SRM Campagnolo 12-Speed Power Meter features a SRM power meter spider plus Campy crank arms. This power meter comes with 12-speed chainrings, making it compatible with 12-speed Campagnolo drivetrains. For compatibility with 11-speed Campagnolo drivetrains, you must use Campagnolo 11-speed chainrings.

SRM Campagnolo 12-Speed Power Meter
SRM Origin Road Carbon Power Meter
The SRM Origin Road Carbon Power Meter uses LOOK carbon crank arms with Trilobe Technology, which allows the crank arm to function in three lengths, 170 mm, 172.5 mm and 175 mm, simply by rotating the pedal inserts. This power meter is available with Miche 12-Speed Campagnolo chainrings, making it compatible with 12-speed Campagnolo drivetrains.

SRM Origin Road Carbon Power Meter
Pros: Accurate, reliable, measures both legs
Cons: More expensive, more work to install
Power Meter Pedals
Power meter pedals can be installed on any crankset. We have several models to choose from.
Pros: Easy to install, works on any bike, can move from bike to bike, don’t have to change crankset
Cons: None